Circuit breaker



Dec. 23, 1958 Filed Dec. 14, 1956 WITNESSES a A w J. D. FINDLEY, JR

CIRCUIT BREAKER -Fig.l.

3 Sheets-Sheet 1 INVENTOR Joseph D. Find|ey,dr.

ATTORNEY Dec. 23, 1958 J D. FlNDLEY, JR 2,866,031

' CIRCUIT BREAKER Filed Dec. 14, 1956 3 Sheets-Sheet 2 Dec. 23, 1958 J,FINDLEY, JR 2,866,031

CIRCUIT BREAKER Filed Dec. 14, 1956 s Sheets-Sheet :5

Fig.4.

United States Patent O F CIRCUIT BREAKER Joseph D. Findley, Jr., ForestHills, Pa., assignor to Westinghouse Electric Corporation, EastPittsburgh, Pa., a corporation of Pennsylvania Application December '14,1956, Serial No. 628,426

7 Claims. (Cl. 200106) This invention relates to circuit breakers, andmore particularly to tripping mechanisms for automatically starts theclosing movement of the armature and the operating mechanism, creates ashock of sufiicient magnitude to start the light-load latch in trippingdirection. Also, the sudden stopping of the armature and the operatingmechanism when they reach the closed position creates a very heavy shockto the framework and mechanism of the breaker which, at times, resultsin'moving the lightload latch mechanism to unlatching position causingfalse opening of the breaker.

It is an object of the invention to provide a circuit breaker embodyingan improved tripping mechanism that does not trip the breaker inresponse to shocks or jarring forces.

Another object of the invention is to provide a'circuit breakerembodying an improved tripping mechanism in which the parts are'disposedand arranged to'resist tripping action in response to shocks.

Another object of the invention is to provide a circuit breakerincluding a solenoid for closing the breaker and embodying an improvedtripping mechanism in which the parts of the tripping mechanism aresupported relative to the direction of the shock of the closing solenoidso that the shock of the closing solenoid does not cause trippingmovement of the parts.

Another object of the invention is to provide a circuit breakerembodying an improved tripping mechanism which prevents trippingmovement in response to shocks and which does not employ inertia membersfor blocking tripping movement of the parts of the tripping mechanism.

Other objects and advantages of the invention will be pointed out in thefollowing description and illustrated in the accompanying drawings,which disclose, by way of example, the principle of the invention andthe best mode, which has been contemplated, of applying that principle.

In said drawings:

Figure 1 is an elevational view, partly in section, of a circuit breakerembodying the principles of the invention.

Fig. 2 is a detail view of the operating mechanism showing saidmechanism in the closed position.

Fig. 3 is a view similar to Fig. 2 but showing the mechanism in thetripped open position.

Fig. 4 is a view similar to Figs. 2 and 3 but showing the mechanism inthe reset and relatched position.

Fig. 5 is a top plan view of the tripping mechanism; and

ice

2 Fig. 6 is a front elevational view of the 'tripping' tn'echanism shownin Fig. 5.

Referring to Fig. 1 of the'drawings, the circuit breaker is of theroll-out type and is mounted on a truck comprising a pair of side plates11 (only one being shown) which are rigidly joined by cross members 13,15, 17 and 19 to form a rigid frame for supporting the circuit breaker.The truck is mounted on wheels 20 to facilitate rolling the breaker intoand out'of a cubicle in orderto connect the breaker in an electricalcircuit and to disconnect it therefrom.

The circuit breaker is of the multipole type (only'one pole being shown)and comprises generally 'a plurality of sets of separable contact means21, a common'operating mechanism 23, a trip device 25 and a closingmeans 27.

The contact means consists generally of stationary contact blocks 29 and31 mounted respec'tively'on upper and lower terminals 33 and 35 which,in turn, are "rigidly supported on a back plate 37 rigidly supported onthe truck.

The specific contact means is fully disclosed in Patent No. 2,717,292,issued September 6, 1955, to Russell Frisch and Paul Olson and assigned'to the assignee of the instant invention, for which'reason only a briefdescription thereof is given.

A switch arm 41 is provided for operating the movable contact and ispivotally mounted on apivotvpin 43 who lower terminal-member 35. Theswitch arm '41 is operatively connected by means of an insulatingoperating rod 45 to the operating mechanism 23. The upperend of theoperating rod 45 is pivotally connected'by a.pin 47 to the switch arm41, and the lower'endof the operating rod is threaded and is connectedby suitable-means such as the nuts 49 to an angular cross bar SI-whichis common to all of the poles of the breaker. The crossbar=51 ispivotally connected at its ends bypivot pins53-(only one being shown) toan operating bellcrank lever55 (Figs. 1, 2, 3 and 4) which is pivotallymounted ona shaft 57 supported in the sidemembers59 of-a generallyU-shaped frame 61. The frame 61 is rigidly supported on the crossmembers 13 and 17 by meansof a plate-62 and is shown partly broken awaymore clearly to show the operating mechanism.

In addition to the operating lever 55, the operating mechanism consistsof a closing lever'63 pivotally mounted on a shaft 65 supported in theside members 59 of the frame 61. The closing lever 63 is connected bymeans ,of a link 67 to the moving armature 69 of a closingsolenoid 27.The link 67 is pivotally connected by'a-pin 70 to the armature 69. Theoperating lever 35 and the closing lever 63 are connected by means of anunderset thrusttransmitting toggle comprising toggle links 73 and '75pivotally connected together by a knee pivot pin 77. The toggle link 73is pivotally connected to one arm ofethe operating bell crank 55 by apin 79, and the togglelink 75 is pivotally connected to the closinglever 63 by a pin 81 which also pivotally connects the link 67totheclosing lever. The closing lever 63 is held in the closed position(Fig. 2) by a spring-biased latch 83, which normally engages a roller 85on the pin 81.

The toggle 7375 is releasably held in-a slightlyiunderset position by alatch member '87 mounted on the shaft 65 for movement relative thereto,A link 89 CQH? nects the knee of the toggle 7375 to the latch member 87,being pivotally connected to the latter by a pin 91, The latch member 87is normally releasably held in latching position by a latch 99 formingpart of the latch? ing and tripping mechanism 25 as seen in Fig. 2. Thelatch member 87 carries a latch roller 93 rotatably mounted on a pin 95(Fig. 5) in the latch member. The latch roller 93 normally engages theinner end'97-of-the balanced main latch 99 pivotally mounted forhorizontal movement by pivot means 101 supported on a cross bar 103which in turn is attached to the cross member 13 by means of bolts 105,and in a bracket 107 secured to the under side of the cross bar 103.

The electromagnetic trip device 25 (Figs. Sand 6) is supported on afront plate 109 which is secured by means of bolts 111 to the cross bar103 and to the cross member 15. The trip device 25 comprises a fixedmagnet yoke 113 rigidly mounted by means of bolts 115 and spacers 117 onan angle bracket 119 which is secured by means of screws 121 to thefront plate 109. A movable armature 123 is rigidly secured to the lowerend of a U-shaped armature lever 125 (Figs. 4 and 6), the spaced sidemembers of which are pivotally mounted on a pin 127 which is supportedby the front plate 109 and in a bracket 129 secured by means of screws131 to the front plate. A member 133 secured to the upper end of thelever 125 carries anadjusting screw 135 which is adapted upon operationof the electromagnet, to engage the outer end 100 of the latch 99 andactuate the latch. The main latch 99 is biased by means of a spring 137against an adjustable stop 139 supported in a bracket 141 secured byscrews 143 to the front plate 109. A spring 145 tensioned between thearmature lever 125 and the bracket 141 biases the armature against astop 147 which is also supported on the bracket 141.

When an overload current occurs, the tripping electromagnet is energizedand operates the latch 99 causing it to release the latch member 87.Upon release of the latch member 87, the toggle 7375 immediatelycollapses to the position shown in Fig. 3 permitting clockwise rotationof the operating lever 55 and opening movement of the switch arms 41 forthe several poles of the breaker.

Collapse of the toggle 73-75 causes counterclockwise rotation of thetoggle link 75 about the pin 81 during which movement a projection 149on the lower end of the toggle link 75 engages and moves the latch 83 toits unlatching position. As soon as the latch 83 is disengaged from theroller 85, a spring 151 connected under tension between the armature 69and the cross bar 103 moves the armature toward the left to itsunattracted position (Fig. 4) where it is arrested by the end of thelink 67 engaging an adjustable stop 153 on the cross member 15. Thismovement straightens the toggle 73- 75 and through the link 89 restoresthe latch member 87 to its latching position as shown in Fig. 4. Thecircuit breaker is now in condition to be closed by operation of theclosing solenoid 27.

Referring particularly to Fig. 1, the closing solenoid 27 comprises, inaddition to the armature 69, a fixed core member 155 rigidly mounted onan end plate 157 which is supported on the cross member 19 and attachedby means of bolts 159 to the frame 61. An energizing coil 161 is mountedon an insulating spool 163 and surrounds the armature 69 and the fixedcore 155.

With the parts of the operating mechanism in the position in which theyare shown in Fig. 4, energization of the closing solenoid 27 attractsthe armature 69 which, through the link 67, moves the closing lever 63counterclockwise about its pivot 65. Since the latch member 87 is nowheld by the latch 99, the link 89 holds the toggle 7375 inthrust-transmitting condition causing it to transmit the closing forceof the armature to the operating lever 55. This thrusts the operatingrod 45 upward and moves the switch arm 41 to the closed contactposition. At the end of the closing stroke the latch 83 reengages theroller 85 and holds the mechanism in the closed position.

The shock of the closing solenoid 27, both in starting the closingoperation and the shock at the end of the closing operation, aredelivered in the direction of the axis of the closing solenoid, that is;from front to rear of the breaker and vice versa. The balanced latch 99is mounted on the vertical pivot 101 and is disposed lengthwise in thedirection in which the shock generated by the solenoid is transmitted.Consequently, such shocks do not tend to move the latch 99 in trippingdirection. The stop 139 for the latch 99 is disposed transversely of thedirection of the shock and also does not transmit a shock force to thelatch to start it in tripping direction. The armature 123 is preventedfrom transmitting a force to the latch 99 in response to the closingshock by disposing the armature pivot 127 axially in the direction ofthe shock. The armature stop 147 is disposed transversely of thedirection of shock, and hence, transmits none of the closing shock tothe armature.

Having described the invention in accordance with the provisions of thepatent statutes, it is to be understood that various changes andmodifications may be made in the particular. embodiment disclosedwithout departing from the spirit of the invention.

I claim as my invention:

1. A circuit breaker comprising power-operated means for closing thebreaker, said power-operated means causing shocks at the beginning andend of a closing operation, said shocks being transmitted in apredetermined direction, tripping means comprising a balanced latchoperable to effect automatic opening of the breaker, said latch havingits length disposed in the direction of said shock so as to preventtripping movement of said latch in response to said shocks, and apivoted armature operable to actuate said latch, said pivoted armaturehaving its axis disposed in the direction of said shocks to preventtransmitting said shocks to said armature in a direction to causetripping movement of said armature.

2. A circuit breaker comprising power-operated means for closing thebreaker, said power-operated means causing shocks at the beginning andend of a closing operation, said shocks being transmitted in apredetermined direction, tripping means comprising a balanced latchpivoted intermediate its ends and operable to effect automatic openingof the breaker, stop means engageable by said latch and disposedtransversely of the direction of the shock to thereby preventtransmission of said shock to said latch, and a pivoted armatureoperable to ac tuate said latch, said pivoted armature having its axisdisposed in the direction of said shocks to prevent transmitting saidshocks to said armature in a direction to cause tripping movement ofsaid armature.

3. A circuit breaker comprising power-operated means for closing thebreaker, said power-operated means generating shocks during a closingoperation, said shocks being transmitted in a predetermined direction,tripping means comprising a balanced latch operable to efiect automaticopening of the breaker, said latch being pivotally supported and havingits length disposed in the direction of the shock so as to preventtripping movement of said latch in response to said shocks, anelectromagnet including an armature movable to operate said latch, andstop means for said armature disposed transversely of the direction ofthe shock to thereby prevent tripping movement of said armature inresponse to said shocks.

4. A circuit breaker comprising power-operated means for closing thebreaker, said power-operated means generating shocks at the beginningand end of a closing operation, said shocks being transmitted in apredetermined direction, tripping means comprising a balanced latchpivoted intermediate its ends and operable to efiect automatic openingof the breaker, stop means engaged by said latch and disposedtransversely of the direction of the shocks to therebypreventtransmission of said shocks to said latch, an armature movable tooperate said latch, and stop means for said armature disposedtransversely of the direction of the shock to thereby prevent trippingmovement of said armature in response to said shocks.

5. A circuit breaker comprising relatively movable contact means andpower-operated means for closing said contact means, said power-operatedmeans causing shocks at the beginning and end of a closing operation,said shocks being transmitted in a predetermined direction, trippingmeans comprising a balanced latch operable to effect opening of thebreaker, electromagnetic means including an armature operable to actuatesaid latch, pivot means pivotally supporting said armature, said pivotmeans having its axis disposed in the direction of said shocks toprevent transmission of said shocks to said armature in a direction tocause tripping movement of said armature.

6. A circuit breaker comprising relatively movable contact means andpower-operated means for closing said contact means, said power-operatedmeans causing shocks at the beginning and end of a closing operation,said shocks being transmitted in a predetermined direction, trippingmeans comprising a latch operable to elTect opening of the breaker,electromagnetic means including an armature operable to actuate saidlatch, pivot means pivotally supporting said armature, said pivot meanshaving its axis disposed in the direction of said shocks to preventtransmission of said shocks to said armature in a direction to causetripping movement of said armature, and a stop for said armaturedisposed transversely of the direction of said shocks to thereby preventtransmission of said shocks to said armature in a direction to causetripping movement of said armature.

7. A circuit breaker comprising power-operated means for closing saidbreaker, said power-operated means generating shocks during closingoperation, said shocks being transmitted in a predetermined direction, abalanced latch pivoted intermediate its ends and operable to effectautomatic opening of said breaker, latch stop means against which saidlatch is biased, said stop means being disposed transversely of thedirection of said shocks to prevent transmission of said shocks to saidlatch, an armature operable to actuate said latch, pivot means pivotallysupporting said armature, said pivot means having its axis disposed inthe direction of said shocks to prevent transmission of said shocks in adirection to cause tripping movement of said armature, and an armaturestop against which said armature is biased, said armature stop beingdisposed transversely of the direction of the shocks to thereby preventtransmission of said shocks to said armature in a direction to causetripping movement of said armature.

References Cited in the file of this patent UNITED STATES PATENTS2,427,998 Wilckens Sept. 23, 1947 2,575,709 Grissinger et al. Nov. 24,1951 2,725,442 Tremblay et al. Nov. 29, 1955

